Restrictor-suction line assembly



Aug. 19418- c. w. SAVIDGE 2,446,853

RESTRICTOR-SUCTION LINE ASSEMBLY Filed Aug. 10, 1945 IN V EN TOR.

W m z W a dams/v7- 46 34 BY g .fid ya jesurf m9 m Patented Aug. 10, 1943 RESTRICTOR- SUCTION LINE ASSEMBLY Clinton W. Savidge, Minneapolis, Minn., assignor to Franklin Transformer Manufacturing Company, Minneapolis,'Minn., a copartnership Application August 10, 1945, Serial No. 609,980

3 Claims. (Cl. 62-127) My present invention relates to a restrictorsuction line assembly for use in connection with a refrigeration installation and it is particularly adapted for freezers in which food is stored at approximately zero degrees F temperature, being also applicable to any mechanical refrigeration system using a restrictor tube.

Qne object of the invention is to provide a restrictor-suction line assembly which can be installed as a unit together with the evaporator coil, the unit requiring only two connections, these being at the refrigerant compressor.

Another object is to provide the rstrictor tube of a refrigeration system enclosed within substantially the entire length of the suction tube from the evaporator to the compressor, the restrictor tube being spirally arranged within the suction tube to improve the operating efilciency of the refrigeration system by a desirable degree of heat exchange between the restrictor and suction tubes as well as by direct gas flow through the suction tube over the restrictor tube. With such an arrangement the suction vapor is superheated to more nearly its condensing temperature, and the liquid leaving the restrictor tube to be gasifled in the evaporator is cooled to more nearly its evaporating temperature.

A further object is to provide protection for the restrictor tube of a refrigeration system by enclosing it in the suction tube of the system, thereby eliminating the tendency of fracture or breakage in the field by reason of the inherently small and fragile character of the restrictor tube by its enclosure in the larger and more rugged suction tube.

Still a further object is to provide a suction line and restrictor tube assembly which may be manufactured inexpensively as one unit and inserted as such into the refrigeration cabinet housing, the unit extending through a single opening at the bottom of the cabinet, thus providing for easier assembly and easier sealing of the insulation to prevent atmospheric heat finding its way to the evaporator through the usual buck housing provided for the passage of individual restrictor and suction tubes.

With these and other objects in view, my invention consists in the construction, arrangement and combination of the various parts of my device whereby the objects contemplated are attained as hereinafter more fully set forth, pointed out in my claims, and illustrated in the accompanying drawings, in which:

Fig. 1 is a diagrammatic view of a refrigeration system including my restrictor-suction line tube assembly; and

Fig. 2 is an enlarged sectional view showing the restrictor tube coiled within the suction tube for heat exchange purposes.

On the accompanying drawing I have used the reference numeral ID to indicate a tank or container for commodities to beheld at low temperatures, such as foods that have been quick frozen." Surrounding the tank I0 is an evaporator coil l2 for absorbing heat from the tank, and the entire assembly of tank In and evaporator coil I2 is embedded in insulation indicated by the reference numeral 14. No attempt has been made to show a cover for the tank In as this, of course, is well known in the art. g

The usual compressor I6 is shown driven by an electric motor l8, and the usual condenser .20 is associated therewith. The parts thus far described have been shown diagrammatically as they form no part of my present invention but illustrate one refrigeration system to which my invention can be applied. The invention, however, is applicable to most other types of mechanical refrigeration systems.

The evaporator I2 has an inlet end I2 and an outlet end 12. An accumulator and liquid drier tube 22 is provided with which the outlet end l2 of the evaporator I2 is connected. The usual enlargement 24 in the outlet portion l2 of the coil I2 is illustrated at 24, its purpose being to more readily determine the final point of cooling in the evaporator.

I provide a suction line formed in two parts, one part being shown at 26 and the other part at 28. The part 26 extends from the accumulator and drier tube 22 toward the compressor and at its point of termination the suction tube portion 28 is connected as by brazing or welding. The end of the portion 28 terminates in a flare which is received in a flared tube fitting 30 connected with the inlet of the compressor H5.

The outlet of the compressor shown at 32 is connected by a tube 34 with the condenser 20, and from the condenser a tube 36 extends to a shutoff valve 38. The shut-off valve has a fitting II for a flared tube, and with'this fitting a restrictor tube feed conduit 42 is connected. The conduit 42 extends to the suction tube 25 and is brazed into it. Within the suction tube it is connected to the restrictor tube 44 which, as clearly shown in Fig. 2, is coiled within the suction tube 26 and is preferably in good mechanical contact with the wall of the suction tube for'metal to metal heat exchange.

The restrictor tube 44 extends into the accumulator and liquid drier tube 22 wherein it has an enlarged coiled portion indicated at 44, which is likewise in metal to metal contact with the wall of the tube 22 for good heat exchange. Finally, the outlet end of the portion 44 of the restrictor tube 44 is connected as by brazing or welding to the inlet end I2 of the evaporator coil l2 with a silica gel drier 45 interposed between the elements l2 and 22.

The motor l8 may be controlled by the usual automatic electric switch 46 having a power element 46 controlled by pressure introduced through a capillary tube 50. The capillary tube 50 extends to a temperature sensing bulb 52 connected at any desired point with the evaporator coil l2.

By placing the restrictor tube 44 within the suction tube and running it substantially throughout the entire length thereof from the compressor it into the drier tube 22 I secure heat exchange by metal to metal contact between the tubes 44 and 26. There is also metal to gas heat exchange between the wall of the restrictor tube 44 which contains hot liquid from the condenser on its way to the evaporator and the cold gas which is returning through the suction line 26. This is secured by the direct contact of the gas with the restrictor tube 44.

The effect of heat exchange along the restrictor-suction line assembly is that the suction vapor is superheated to more nearly its condensing temperature and the liquid leaving the restrictor tube to enter the evaporator coil l2 where it becomes gasified is cooled down to a temperature nearer its evaporating temperature. The accumulator and liquid drier tube 22 provides further drying or gasiiying of the liquid vapor returning from the low side in the suction line and offers further cooling of the liquid contained in the restrictor tube just prior to its entering the evaporator coil The drying or gasifying feature of the accumulater and drier tube 22 manifest the objective of eliminating or materially reducing the possibility of drawing liquid refrigerant back into the compressor. The tube 22 serves two functions in accomplishing such objective: the first function is to provide a reduced pressure chamber which promotes the further vaporization of any liquid that might emerge from the outlet end of the refrigeration system; the second function is to act as a reservoir which will accommodate a slightly variable refrigerant charge without affecting the operation of the system or the compressor. The velocity of flow of refrigerant through the enlarged area of the tube 22 is naturally slower than that through the tube 26 which provides for more time for final vaporization to take place.

With my arrangement no external heat exchanger coil is required because of the spiraling of the restrictor tube within the suction tube. The resulting structure is one which can be prefabricated at the factory and all joints of the evaporator and its restrictor-suction line assembly brazed or welded so that in the field the only connection necessary is that of the two fittings 30 and 40. These, of course, are necessary for interchange of compressor-motor units and repairs in the field on the refrigeration system.

My arrangement also fully protects the fragile restrictor tube from damage and the over-all cost of the refrigeration installation is reduced due to the elimination of outside heat exchange coils and a reduction in number of fittings required. The points of possible leakage are reduced to two, which is also an obvious advantage.-

The spiral arrangement of the tube 44 within the tube 26 makes the device readily adaptable for great variations in refrigeration rate as the coils of the tube 44 can be more closely spaced where more restrictor tube in relation to suction tube is found necessary. The restrictor-suction tube unit is thereby readily prefabricated to meet any required specifications.

The assembly is also susceptible to ready dehydration of the entire system at the factory where all necessary tests can be made and the refrigertion box and the machinery shipped out as either separate units or connected units, as desired.

Some changes may be made in the construction and arrangement of the parts of my device without departin from the real spirit and purpose of my invention, and it is my intention to cover by my claims such modified forms of structure or use of mechanical equivalents as may be reasonably included within their scope.

I claim as my invention:

1. A tube assembly adapted for connection in the refrigerant line of a refrigeration system, said tube assembly comprising, in combination, an outer suction tube, said suction tube being elongated and pipe-like in formation and having an enlarged extension at one end, and a restrictor tube coiled in said suction tube and in said enlarged extension in contact with the walls thereof, said restrictor tube extending out of said enlarged extension and out of the opposite end of said suction tube.

2. A tube assembly adapted for connection in the refrigerant line of a refrigeration system, said tube assembly comprising, in combination, an outer suction tube, said suction tube being elongated and pipe-like in formation and having a flared extension at one end and an enlarged cylin-' drical extension at the other end, said flared and cylindrical extensions being adapted for connection with said refrigerant line, and a restrictor tube coiled in said suction tube and in said cylindrical extension in contact with the walls thereof, said restrictor tube extending out of said flared and cylindrical extensions adapted for connection in said refrigerant line.

3. In a refrigeration installation of the character disclosed, having an evaporator, compressor and condenser mechanism, and a connection assembly between said evaporator and said compressor and condenser mechanism, said connection assembly comprising, in combination, a suction tube, an enlarged drier tube at one end of said suction tube, a restrictor tube coiled inside said suction tube and drier tube, and extending out of the respective ends thereof, said drier tube being adapted for connection with the outlet of said evaporator, said restrictor tube at the end thereof extending out of said drier tube being adapted for connection with the inlet of said evaporator, said suction tube at the end thereof opposite said drier tube being adapted for connection with said compressor mechanism, and said restrictor tube being adapted for connection at said opposite end with said condenser mechanism.

CLINTON W. SAVIDGE.

REFERENCES CITED UNITED STATES PATENTS Number Name Date Rued Apr. 30, 1918 Carpenter Jan. 29, 1946 

